Refrigeration



March 16, 1943. c. T. AsHBY REFRIGERATION Filed Nov. 16, 1939 2Sheets-Sheet 1 Patented Mar. 16, 1943 UNITED STATES PATENT oFFlcE2,314,064 nnFmGERA'rroN Carl T. Ashby, Evansville, Ind., assgn'or toServel,

Inc., New York, N. Y., a corporation of Dela- Ware Application November16, 1939', Serial No. 304,638 claims. (crea- 119.55

My invention'relates to refrigeration, and more y particularly concernscooling effected in a refrigerator cabinet.

It is an object ofthe invention to provide an improvement for cooling arefrigerator cabinet whereby several places of cooling are obtained -inone or more of which a higher humidity may be ment so that the air inthe separate chamber is.

maintained at a higher humidityrwith less dehydration of food productsstored therein.

Another object of the invention is to provide.

several places of cooling with the aid of a refrigeration system havinga plurality of cooling elements, the system being so constructed and.

arranged that under all operating conditions liquid refrigerant isdelivered to the cooling elements in such a manner that one of thecooling elements is capable of maintaining one of the places of coolingat a relatively high humidity.

The invention, together with the above and -other objects andradvantagesthereof, will be ,in section, of a refrigerator embodying the invention;

Fig. 2 is a front elevation of the refrigeratorv with which therefrigeration system in Fig. 1 is associated, the door being in its openposition;

Fig. 3 is an enlarged fragmentary view taken on l lines 3 3 of Figs. 2and 4; v

Fig. 4 is a vertical sectional view taken on line 4 4 of Fig. 3;

Fig. 5 is a side vertical sectional view taken on line 5 5 of Fig. 4;and

Fig. 6 is a vertical viewv taken on line 6 6 of Fig. 4.

Referring to Figs. l and 2, I havevshown the.

invention embodied in a refrigerator comprising a cabinet I0 having aninner Ametal shell I I arranged to be supported within an outer metalshell I2 and insulated therefrom with any suitable insulating materialI4. The inner shell I I forms a thermally insulated storage space I5into which access maybe had Iby a door I6 hinged to the front of thecabinet. Within the storage space I5 are arranged several coolingelements which together constitute a cooling unit or evaporator I'I of arefrigeration system.

The cooling unit or evaporator I'I forms a part of a refrigerationsystem of a uniform pressure absorption type, generally as described inPatent No. 2,037,782 to William R. Hainsworth, in which an auxiliarypressure equalizing gas is employed.

In addition to the cooling unit or evaporator I'I, such a systemincludes a generator I8, a condenser I9, and an absorber 20 which areinterconnected in a manner well known in the art and` which will brieflybe described hereinafter. The

system contains a solution of refrigerant in absorption liquid, such asammonia in water, vfor example, and also an auxiliary agent or inertgas, such as hydrogen.

y The generator I8 is heated in any suitable manner, as by a gas burner2I, for example.

vduits 24, 25 and 26, as will presently be de scribed.

Refrigerant fluid in evaporator I'I evaporates and diffuses into inertgas which enters the lower part thereof through a conduit 21. 'I'herefrigerant iiuid in evaporator I1 evaporates and diffuses therein intothe inert gas to produce a refrigerating effect. The rich gas mixture ofrefrigerant vapor and inert gas formed in evaporator I1 flows from theupper part thereof through conduits 28 and 29, inner passage 30 of a gasheat exchanger 3|, and conduit 32 into the lower part of absorber 20.

In absorber 20 the rich gas mixture flows counter-current to downwardlyflowing weak absorption liquid which enters through a conduit 33. Theabsorption liquid absorbs refrigerant vapor from the inert gas, andinert gas weak in refrigerant flows from `absorber 20 through a conduit34, outer passage 35 of gas heat exchanger 3|, and conduit 21 into thelower part of evaporator I1. A

Absorption liquid enriched in refrigerant ows from the lower part ofabsorber 20 through a conduit 36, outer passage of a liquid heatexchanger 31, and conduit 38 into generator I8. Liquid is raised in thegenerator by a thermosiphon tube 39 and flows back to the generatorthrough standpipe 22. Refrigerant vapor expelled out of solution ingenerator I8, together with refrigerant vapor entering throughthermosiphon tube 39, flows upwardly through standpipe 22 and conduit 23into the condenser I9, as explained above.

The absorption liquid from which refrigerant has been expelled flowsfrom generator I through a conduit 4I), inner passage of liquid 'heatexchanger 31, and conduit 33 to the upper part of absorber 20. Thiscirculation of absorption liquid results from the raising of liquid bythermosiphon tube 39.

Heat liberated with absorption of refrigerant vapor in absorber 2D istransferred 'to a suitable cooling medium which circulates through acoil 4I arranged in heat exchange relation with the absorber. The coil4I isconnected by conduits 42 and 43 to an air-cooled condenser 44. Thecoil 4I, condenser 44, and connecting conduits 42 and 43 form a closedcircuit which is partly filled with a volatile liquid that vaporizes incoil 4| and liquees in condenser 44. Liquid evaporating in coil 4I takesup heat from absorber 20, and the vapor liquefying in condenser 44 givesup heat to surrounding air.

The outlet end of condenser I9 is connected by conduit 45, vessel 46,and conduit 41 to the gas circuit, as at the upper end of conduit 29,for example, so that any inert gas may pass through the condenser andflow into the gas circuit. Refrigerant vapor not liquefied in condenserI9 flows through conduit 45 to displace inert gas in vessel 46 and forcesuch gas through conduit 41 into the gas circuit. In this manner thetotal pressure in the system is raised where- -by an adequate condensingpressure is obtained to insure condensation of refrigerant vapor incondenser I9.

The circulation of gas in the gas circuit including evaporator I1 andabsorber 20 is due-to the difference in specific weight of the columnsof inert gas rich and weak, respectively, in refrigerant vapor. Sincethe rich gas is heavier than the weak gas, a force 'is produced ordeveloped for causing flow of the rich gas from evaporator I1 toabsorber 20 and flow of weak gas from absorber 26 to evaporator I1.

The evaporator I1 includes an upper cooling element 48, an intermediatecooling element 49, and a lower cooling element 50. Liquid refrigerantentering upper cooling element 48 through conduit 24 flows downward incounter-flow to inert gas which flows upwardly and enters lower coolingelement 50 through conduit 21. Liquid refrigerant also entersintermediate cooling element 49 through conduit 25 and lower coolingelement 50 through conduit 26, as explained above, such liquidrefrigerant flowing countercurrent to the upwardly owing inert gas.Since the inert gas flows 'first through the lower cooling element 50and then through intermediate cooling element 49 and lastly throughupper cooling element 48, the gas in upper cooling element 48 contains agreater amount of refrigerant vapor than the gas in the intermediate andlower cooling element 49 and '50, and the gas in intermediate coolingelement 49 contains a greater amount of refrigerant vapor than the gasin lower cooling element 50. The partial pressure of refrigerant vaporis, therefore, higher in cooling' element 49 than in cooling element 50,and evaporation of liquid refrigerant takes place at a highertemperature in the intermediate cool ing element than in the lowercooling element 50. Also, the partial pressure of refrigerant vapor ishigher in upper cooling element 48 than in intermediate cooling element49, and evaporation of liquid refrigerant takes place at a highertemperature in the upper cooling element than in the intermediatecooling element The intermediate cooling element 49 is provided with aplurality of heat transfer fins 5I to provide a relatively extensiveheat transfer surface for cooling air in storage space I5. Air cooled bythermal transfer with intermediate cooling element49 flows downward inspace I5 to replace warmer air which flows upward and passes over thesurfaces of the intermediate cooling element.

The lower cooling element 50 is arranged in heat exchange relation witha shell 52, as shown Amost clearly in Fig. 4, the shell 52 having aplurality of compartments 53 to receive trays 54 for freezing ice cubesand the like. The shell 52 has a limited heat transfer surface which maybe employed to assistintermediate cooling element 49 for cooling air instorage space I5.

Thevupper cooling element 48 is arranged in a housing or casing 55 toprovide a separate chamber 56 within storage space I5. 'Ihe uppercooling element 48 is located in the upper part of separate chamber 56and provided with a plurality of heat transfer fins 51 to provide arelatively extensive heat transfer surface for cooling air in chamber56.

In order to locate the cooling elements 48, 49 and 50 of evaporator I1in storage space I5, the rear insulated wall of the space is providedwith an opening to receive a removable wall section 58. The conduitsconnecting evaporator I1 and the other parts of the refrigerationsystem' extend through the removable wall section 58. As

shown most clearly in Figs. 4 and 5, the casing 55 is secured at 59 and60 to the inner shell II to hold the casing in position within storagespace I5. A door 6I is pivotally mounted at the front of casing 55 toprovide access into the sep- 5 arate' chamber 55.

The lower cooling element 50 is normally operated below the freezingtemperature of water andforms the ice freezing portion of evaporator I1.The intermediate cooling element 49 operates at a higher temperaturethan lower cooling element 50, as explained above, and is employedprimarily for cooling air in space I5 to maintain the latter at a lowtemperature for properly preserving foods stored therein.

The air in chamber 56 is maintained at a higher humidity than that inspace I5 with the vresult that less dehydration of food products takesplace in this chamber. This is due to the fact that cooling element 48operates at the highest temperature of any of the cooling ele-,- ments.-so that lessl water vapor is condensed from air in chamber 56 whichflows in thermal contact with upper cooling element 48.

With the above described improvement, it will be clear that severalplaces of cooling are provided in a refrigerator cabinet with one oftheplaces being maintained at a relatively high humidity. The separatechamber. 56 is eifectively cooled b'y locating the upper or highesttemperature cooling element 48 in the upper part of casing 55. When thedoor 6I of casing 55 is closed substantially no circulation of .airtakes place between storage space I5 and chamber 56,' so that there isno displacement of air at a relatively high humidity in chamber 56 byair at a lower humidity in storage space I5. While the lowesttemperature cooling element 50 has been described above as beingemployed to assist intermediate cooling element 49 for cooling air instorage space I5, the lower temperature-cooling element 50 may beinsulated, if desired, and intermediate cooling element 49 may beemployed to effect cooling of storage space I5. Cooling of air instorage space I is also effected by air flowing in thermal contact withVcasing 55. By providing chamber 56, however, a' sepa, rate space forstoring food is obtained which is at a sufficiently low temperature forfood preservation and yet is maintained at a relatively high humidity tolessen dehydration of foods. v

In order to keep evaporator II in a Ldesired temperature range, theburner 2l may be controlled in response to a temperature conditionaffected by evaporator I1, as shown in Patent No. 2,123,921 toAndersson, for example, -the disclosure of which may be considered to beincorporated in this specification. If all of the liquid refrigerantformed in condenser I9 were delivered to the upper cooling element 48and thence through the intermediate and lower cooling elements 49 and50, the upper cooling element under certain operating conditions, as atlow load, for example, may reach a lower temperature than desired. Inorder that upper cooling element 48 will always be at a temperature toinsure maintenance of a relatively high humidity in chamber 56, liquidrefrigerant first formed in condenser I9 is delivered to theintermediate and lower cooling elements 49 and 50, and liquidrefrigerant subsequently formed in the condenser is delivered to uppercooling element 48." One manner of accomplishing this is shown in Fig. 1wherein refrigerant vapor expelled from solution in generator IIl fiowsupwardly through conduit 23 into a first condenser section I9a in whichvapor is liquefied. Liquid refrigerant formed in condenser section I9aiiows through conduits 62 and 25 ntothe upper part ofv intermediatecooling element 49 and thence int lower cooling element 50.

Refrige'rant vapor not liquefied in the first condenser section |9aflows therefrom through the upper part of conduit 62 and a conduit 63into a second condenser section |917 in which v apor is liquefied.Liquid refrigerant formed in condenser section I9b flows throughconduits 64 and 26 into lower cooling element '.i 0.-11 Refrigerantvapor not liquefied in second condenser section I9b fiows through theupper part of conduit 64 into a third condenser section I9c in whichvapor is liquefied. Liquid refrigerant formed in condenser section I9c.ows through conduit 24 into the upper cooling element 48.

Instead of delivering liquid refrigerant from second condenser section|9121v into the .lowercooling element 59, liquid refrigerant may beconducted from this condenser section into upper cooling element 48. ByYtaking into consideration the manner in which liquid refrigerant isdelivered to the several cooling elements of evaporator I'I, uppercooling element 48 can always be maintained in a desired temperaturerange under the different operating conditions encountered. Thus, whenthe heat input to generator I8 by burner `2I is reduced and lessrefrigerant vapor is expelled from solution at low load, all of theliquid formed in condenser, I9 will not be delivered to upper coolingelement -and liquid` refrigerant ows from the second condenser sectionI9b through conduits 64 and 26 into lower cooling element 50. Since norefrigerant vapor is liquefied in the third condenser section I9c, underthe operating `conditions assumed, no liquid refrigerant is suppliedthrough conduit 244 into the upper cooling element4l. However, when theload increases and refrigerant vapor is expelled from solution in lgenerator I0 at such a rate that allof the refrigerant vapor is notliqueed in the first and second condenser sections I9a and I9b, andrefrigerant vapor passes into thethird condenser section |90, asexplained above, liquid refrigerant is then supplied to the uppercooling element 48. In the foregoing explanation and in the claims theword load is intended tomean the quantity of heat external of therefrigeration apparatus that is removed per unit of time by the coolingunit or evaporator I1.

While a single embodiment; of the invention -has been shown anddescribed, such variations and modifications are contemplated as fall.within the true spirit and scope of the invention, as pointed out inthe following claims.

What is claimed is:

1. A refrigerator having a thermally insulated storage space, anabsorption type refrigeration system including upper, intermediate, andlower cooling element .connected for upward flow of auxiliary agent inseries and downward flow of cooling agent in the presence of auxiliaryagent, and a compartment in the upper part of said storage spacearranged to be cooled by said upper cooling element, said intermediatecooling element being disposed in the upper part of said storage space,said lower cooling element having thermally connected therewith achamber for freezing ice and the like, said system including a condenserhaving a plurality of sections in which vaporous cooling agent isliquefied and from which the liquid cooling Aagent is 'delivered to saidcooling elements, and connections whereby liquid formed in one ofsaidcondenser sections is delivered to said intermediate and lowercooling elements, and liquid subsequently formed in another of saidcondenser sections is delivered to said upper cooling element.

'2. A refrigerator having a thermally insulated storage space, anabsorption type .refrigeration system including upper, intermediate, andlower cooling elements connectedy for upward ow of auxiliary agent inseries and downward iiow of cooling'agent in the presence of theauxiliary cluding a condenser having three sections con-4 nected inseries to receive vaporous cooling agent, the section in which vapor isfirst liquefied being connected to deliver liquid cooling agent to saidintermediate cooling element, the section in which Vapor is subsequentlyliqueed being connected to deliver liquid to said lower cooling element,and the section in which Vapor is last liquefied beingconnected todeliver liquid to said upper cooling element.

3. A refrigerator having a thermally insulated storage compartment, aseparate high humidity compartment, and refrigeration apparatus forcooling said compartment and employing evaporation of refrigerant uid inthe presence of inert gas, said apparatus including a plurality ofevaporators in which said evaporation may take place and through whichsaid inert gas flows serially so that evaporation of liquid takes place,at different temperatures in said different evaporators, one of saidevaporators being arranged for freezing water or the like, another ofsaid evaporators at a higher temperature being arranged to cool air insaid storage compartment, and a third one of said evaporators at a stillhigher temperature being arranged to cool air in s'aid high humiditycompartment, and said refrigeration apparatus including a liquidsupplier which supplies liquid to said last evaporator only when theload is at or above a predetermined value.

4. A refrigerator having a storage compartment, a high humidity,compartment in heat exchange relation with said storage compartment,refrigeration apparatus comprising a plurality of parts and connectionstherebetween, said parts including a liquid refrigerant supplier and aplurality of cooling elements in which liquid refrigerant evaporates toproduce a cooling effect, each of said compartments being arranged to becooled by one of said cooling elements, said connections includingconduits for conducting liquid from said liquid refrigerant supplier tosaid cooling elements, and said parts including said connections beingso constructed and arranged that said cooling element for said highhumidity compartment is capable of producing a cooling effect byevaporation of liquid refrigerant therein only when the load is at orabove a predetermined value.

5. A refrigerator having a plurality of compartments, one of ,Saidcompartments being in heat exchange relation with another of saidcompartments, refrigeration apparatus comprising a plurality of partsand connections therebetween, said parts including a liquid refrigerantsupplier and a plurality of evaporators in which liquid refrigerantevaporates to produce a cooling effect, said evaporators being operableat different temperatures, with each of said compartments being arrangedto be cooled by one of said evaporators, said connections includingconduits for conducting liquid from said liquid refrigerant supplier tosaid evaporators, and said parts including said connections being soconstructed and arranged that one of said evaporators for cooling one ofsaid compartments is capable of producing a cooling effect byevaporation of liquid refrigerant therein only when the load is at orabove a predetermined value.

CARL T. ASHBY.

